The engineered chromosome bears a duplication of a ~3 Mb segment of Chr 11 containing 19 genes including Cops3 (a.k.a. Csn3), which only in the duplicate copy is interrupted (and inactivated) by an insertion; the entire coding region, but not the final, untranslated exon of Rnf112 (formerly Zfp179); and all the intervening DNA. The insertion in Cops3 contains a tyrosinase minigene and a transgene comprising wild-type agouti cDNA under control of the human keratin 14 promoter. (J:83302)